Boiler



FIG. 1 is a perspective view of a first embodiment of the boiler, particularly showing the inventive design thereof;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a left side view thereof;

FIG. 5 is a right side view thereof;

FIG. 6 is a top view thereof;

FIG. 7 is a bottom view thereof;

FIG. 8 is a perspective view of a second embodiment of the boiler, particularly showing the inventive design thereof;

FIG. 9 is a front view thereof;

FIG. 10 is a rear view thereof;

FIG. 11 is a left side view thereof;

FIG. 12 is a right side view thereof;

FIG. 13 is a top view thereof; and,

FIG. 14 is a bottom view thereof. 

The ornamental design for a boiler, as shown and described. 